Space telephony.



No. 803,199. PATENTED OCT. 31, 1905. J. S. STONE.

SPACE TELEPHONY.

APPLICATION FILED JUNE 20,1905.

2 SHEETS-SHEET 1.

No. 803,199. PATENTED OCT. 31, 1905. J. S. STONE.

SPACE TELEPHONY.

APPLICATION FILED JUNE 20,1905.

2 SHBETS-SHEET 2.

IINITED STATES PATENT orrion.

Specification of Letters Patent.

Patented Oct. 31, 1905.

Application filed June 20,1905. Serial No. 266,158.

To aZZ whom, it may concern:

Be it known that 1, JOHN STONE STONE, a citizen of the United States,and a resident of Cambridge, in the county of Middlesex and State ofMassachusetts, have invented a certain new and useful Improvement inSpace Telephony, of which the following is a specification.

This invention relates to the art of transmitting vocal or other sounds,including articulate speech, from one station to another by means ofelectromagnetic waves without the use of wires to guide the waves totheir destination; and it relates more particularly to the art andapparatus whereby theelectromagnetic waves are developed by producingelectrical vibrations or oscillations in an elevated conductor,preferably vertically elevated, in accordance with the vibrations'of theair accompanying such vocal or other sounds. It also relates to areceiving system by means of which the energy of such waves so modifiedmay be selectively received and the energy of the resulting electricaloscillations converted into sonorous vibrations corresponding to thesounds produced at the transmitting station.

Certain of the fundamental or underlying principles of the inventionhave been fully set forth in my prior Letters Patent, among othersLetters Patent Nos. 7 1 1,756, 7 37 ,170 and more detailed descriptionof these principles,

as well as for the general construction of the apparatus and circuitarrangements employed, than is necessary to set forth herein.

The invention may best be understood by having reference to the drawingswhich accompany and form a part of this specification and whichdiagrammatically represent various forms of apparatus and circuitarrangements whereby the hereinbefore stated objects may be realized.

1n the drawings,

Fig. 1 represents a transmitting system in which the amplitude of apractically continuous train of electrical oscillations may be modifiedin accordance with thevibrations of the air which accompany the sound tobe reproduced at the receiving station.

Fig. 2 represents another form of transmitting system by which theobjects of the present invention may be eifected.

Fig. 3 represents a modification of the transmitting system shown inFig. 2.

Fig. 4: represents still-another form of space telephone transmittingsystem.

Figs. 5 and 6 represent two forms of receiving system by which theenergy of simple harmonic electromagnetic Waves of definite frequencymay be selectively received and the energy of the resulting electricaloscillations converted into sound Waves by means of electro-receptivedevices quantitatively responsive to said electrical oscillations.

In the figures D is a generator of unidirectional electromotive force.

- S is a spark gap.

n-s is a magnet.

C C1 C2 C3 C3 and C1 are condensers.

L L1 L2 L3 are inductance coils.

T T are transmitters.

M M M are transformers.

B is a battery.

R is an adjustable resistance.

K is an electro receptive device herein shown as a bolometer fine wireor strip.

121 is an electro receptive device herein shown as a condenser telephonereceiver.

n is a magnetic telephone receiver.

In Figs. 1, 2, 3 and 4: the circuits lettered G are continuouslyoscillating'circuits of the general type described in my Letters PatentNo. 7 67,983, and each is adapted to develop a continuous train ofelectrical oscillations of definite frequency and substantially constantamplitude, as more fully set forth in said Letters Patent. In thesefigures D are direct current generators, and the circuits at D b arecircuits of large electro-motive force and high resistance. A permanentmagnet n-s may be associated in the usual way with each spark gap S andperform the usual function of such magnet in connection with the sparkgap, namely, that of extinguishing the arc. In Figs. 2, 3 and 4 thespark gap may be a multiple spark gap whose discharging surfaces ormetallic parts are of large conductibility for heat, as set forth in theLetters Patent to Elihu Thomson No. 444,678, dated January 13, 1891, inwhich case the arc is self-extinguishing, thereby rendering theemployment of the magnet unnecessary, or'the electrodes may be hollowmetallic bodies, each provided with a vent and filled with Water, inwhich case the temperature of such electrodes cannot exceed that of theboiling point of water. The circuits lettered R are resonantor resonatorcircuits each attuned to the frequency place.

of the continuous trains of electrical oscillations developed by thecircuits G and, being interposed each between the elevated conductor andthe generator circuit to which it is attuned, render the oscillationsimpressed upon the elevated conductor simple harmonic in form andincrease the amplitude of such oscillations by the cumulative effect ofelectrical resonance.

In Fig. 1 the required variations or modifications in the amplitude ofthe electrical oscillations developed in the continuously oscillatingcircuit G, are obtained by varying the length of the spark gap S, atwhich the disruptive discharge of the condenser C1 takes A convenientmeans for so varying the length of the spark gap consists in employingthe transmitter diaphragm as one terminal of said spark gap. Oneconcrete embodiment of this form of transmitter T is illustrated in Fig.2 of U. S. Letters Patent 638,152, granted Nov. 28, 1899, upon myapplication filed Dec. 15, 1896. The potential difference to which theplates of the condenser C1 may be charged before a disruptive dis chargetakes place across the spark gap S, depends upon the length of said gap,and the current necessary to charge the condenser is proportional tothis potential diiference between the plates. lt follows that by varyingthe length of this air gap I may vary the amplitude of the oscillatorycurrent in the primary circuit a C1 L1 6. By talking into thetransmitter diaphragm which forms one of the spark gap terminals, thelength of the spark gap is varied in a manner corresponding to thesonorous vibrations accompanying the voice waves and such variations arereproduced in the amplitude of the oscillations developed in theresonant circuit R and in the amplitude of the oscillations impressed bysaid resonant circuit upon the radiating conductor Vand, there fore, inthe amplitude of the electromagnetic waves radiated by said conductor.The resonant circuit R may, however, be omitted and the primary circuitG associated directly with the elevated conductor system. It is to beunderstood that 1 do not limit myself in any case to the inductiveassociation of a transmitting or a receiving circuit with the elevatedconductor system, but may employthe modes of conductively connecting theclosed and open oscillating circuits which are described in my LettersPatent 767,989 and 767,990.

In Fig. 2 the means whereby the required variations or modifications inthe amplitude of the electrical oscillations developed in the elevatedconductor system are efiected consist of the resonator circuit 30 andthe variable resistance transmitter T. By means of the generator circuitG electrical oscillations are developed in the resonator circuit R, andsaid electrical oscillations experience an impedance in passing theprimary winding 10 included in the resonator'circuit, the magnitude ofsaid impedance depending, according to well known principles, upon theimpedance which the corresponding secondary winding 81 and its circuitoffer to electro-motive forces of the particular frequency to which suchsecondary circuit is attuned. Since the current of any given frequencywhich flows in a resonator circuit depends upon the impedance of thecircuit to the electro-motive force vibrations of that frequency, we maysay that the impedance offered by a given primary helix to currentcomponents of any given frequency depends upon the current of thatparticular frequency induced by it in the secondary. The secondary helixs1 develops in the resonator circuit 30, currents which are practicallysimple harmonic and therefore any variation in the electromagneticconstants of such secondary resonator circuit will produce acorresponding variation in the impedance of the primary helix. Suchimpedance variation produces a corresponding variation in the intensityof the oscillations developed in the resonator circuit R, and thereforea corresponding variation in the amplitude of the resultingelectromagnetic waves radiated by the elevated conductor V.

A third embodiment of the present invention is illustrated in Fig. 3, inwhich the circuit 30 is inductively associated with the generatorcircuit G, and is adjusted to a condition of maximum efiiciency. By thevariation of the resistance of the transmitter T, the impedance of theprimary p is correspondingly varied and this produces a correspondingvariation in the amplitude and also in the frequency of the resultingoscillations in cir cuit G. Hence the response of the resonant circuit Rand the elevated conductor system tosuch electrical oscillations islikewise correspondingly Varied. This results in the radiation of apractically continuous train of electromagnetic waves modified as totheir amplitude in accordance with the sonorous vibrations accompanyingthe sounds uttered before the diaphragm of the transmitter T. It is tobe observed that in the system of Fig. 3 in which the frequency as wellas the amplitude of the electrical oscillations developed in thesonorous circuit G is varied by varying the natural period and impedanceof said circuit, the ultimate result is the same as in Figs. 1 and 2,namely, that the amplitude of a practically continuous train ofelectromagnetic waves of substantially uniform amplitude is modified inaccordance with the sonorous vibrations of articulate or other sounds,because of the forced simple harmonic oscillations developed in theelevated conductor system which is preferably attuned as to itsfundamental to said predetermined, definite frequency.

A fourth embodiment of the broad invention hereinafter claimed, is shownin Fig. 4.

In this figure the required variations are produced by speaking into thetransmitter T, which is included in a circuit with a battery B and theprimary of the transformer M, which transforms the current in theprimary to a very high potential current in the secondary circuitcontaining the condenser U", which serves to partly neutralize theinductance of. the secondary and to exclude therefrom the current of thebattery D. Currents developed in this secondary circuit co-operate withthe battery D in producing sparks at the gap S, and modify the amplitudebut not the period of the resulting oscillations in the circuit Gr.

The frequency of the simple harmonic electrical oscillations developedin the radiating conductor by the continuously oscillating circuits G,is of course far above the limit of audibility, but by the means alreadydescribed such oscillations have their amplitude modified in accordancewith the sound waves which affect the transmitter T, and accordinglythere results the radiation of .a continuous train of electromagneticwaves having its amplitude correspondingly modified. Such continuoustrain of high frequency simple harmonic electromagnetic waves, whoseamplitude is so modified by the slower periodic vibrations of thefrequency corresponding to the pitch of an audible tone or combinationof tones, develops oscillatory electric currents of correspondingfrequency and modified amplitude by impinging upon an elevated receivingconductor at a distant station. Such currents so developed in theelevated receiving conductor system may be selectively absorbed byproperly designed resonant receiving circuits, attuned to the frequencyof such currents. Such receiving systems are by way of example shown inFigs. 5 and 6, although it is to be understood that many other forms ofreceiving systems disclosed in my prior patents are suitable for thispurpose. The bolometer receiver K is quantitative in action,andaccordingly the current intensities in the local circuit a K R of saidreceiver correspond to the intensities or amplitudes of the electricaloscillations absorbed by the resonant circuit 33 in which the bolometeris included and, inasmuch as the amplitudes of. such oscillationscorrespond to the sonorous vibrations of the sounds produced at atransmitting station, it follows that the current intensities in said10- cal circuit likewise correspond to said sonorous vibrations and thatif the device 91 be a ous vibrations.

veloped in said resonant circuit.

It is not necessary however to employ such receiving system including anoscillation responsive device K and an associated translating device 01.because, as shown in Fig. 6, the functions of these two elements may beperformed by a single apparatus, which is both an oscillation responsivedevice and a translating device. The circuit arrangements of Fig. 6 areidentical with those of Fig. 5, except that in the resonant circuit 33'is included an electric translating device an con- 'stituting one of thetuning elements of said resonant circuit and adapted to utilize in itsoperation the energy of the oscillations de- In that embodiment of theinvention shown in Fig. 6, such translating device consists of acondenser telephone C3, such for example as described in connection withFig. 12 of my reissue Letters Patent No. 12,149, and such condensertelephone constitutes one of the tuning elements of the resonant circuit33 and is adapted to utilize in its operation the potential energy ofthe oscillations developed in said circuit.

When such telephone receiver is subjected to a continuous and uniformvibratory or oscillatory current, whose frequency of vibration is abovethelimit of audibility or is higher than the pitch of the highest toneto which the moving parts of the receiver are capable of responding, thetelephone receiver remains silent. hen, however, the intensity oramplitude of the high frequency currents to which such receiver issubjected is not uniform, but is subjected to slower periodic vibrations-whose frequency corresponds to the pitch of an audible tone orcombination of tones to which the moving parts of the re ceiver arecapable of responding, the receiver reproduces suchtonesorcombinationsoftones. In the system shown in Fig. 6 high frequencyoscillatory currents of practically continuous duration are developed inthe resonant circuit 33 by the practically continuous trains ofelectromagnetic waves radiated by the systems shown in Figs. 1, 2, 3.and 1, and the variations in the amplitude or intensity of such highfrequency oscillatory currents correspond to the variations in theamplitude or intensity of the electromagnetic Waves which create them.The rate of vibration of the oscillatory currents so developed in theresonant circuit 33 is, of course, so great as not to produce an audiblesound in the telephone receiver m, but the latter responds to thevariations in the amplitude of these vibrationsand therefore reproducesthe spoken words which control or vary the particular transmitter T thateffects the variations in the i cuits in general, it is not all suchcircuits &

which are available for use in the manner described. For the purposes ofthis invention it is desirable that these circuits have a very theinductance and electrostatic capacity of the circuits be of the elastictype and, for this purpose, dielectric and magnetic hysteresis, Foucaultcurrents and closed secondary reactions generally, should be avoided orminimized by any means best adapted for the purpose. Specifications forthe design of inductances and electrostatic capacities suitable for usein such circuits and the proper relations that must subsist between thevarious members of a complex of circuits so that each circuit is notmaterially aflected by its association with the other circuit orcircuits have been fully set forth in my Letters Patent Nos. 714,756,714,832, 737,170 and in other Letters Patent issued on my application onAug. 16, 1904:, to which reference may therefore be had.

The impedance presented by a resonant circuit to the passage of simpleharmonic alternating or oscillating currents depends upon the frequencyof said currents, being lowest when said frequency is that to which theresonant circuit is attuned and increasing as the frequency is increasedor decreased from that value, and the rate of such increase of impedancewith variations in frequency depends upon the selectance of the resonantcircuit.

The term selectance or selectivity has been defined by me as the abilityof a resonant circuit to differentiate currents of the frequency towhich it is attuned from currents of other. frequencies. idepends uponthe se- L O R the inductance, C the capacity, and R the dissipativeresistance of the resonant circuit. This function will be seen toconsist of the ratio of the electromagnetic to the electrostatictime-constant of the circuit, namely, L/R and CR respectively. function,when the factors comprised in it are expressed in the proper units, isthe measure of the number of oscillations the circuit will executebefore the amplitude of such oscillations will fall to a definitefractional part of its initial value after its electrical equilibriumhas been disturbed, and therefore it represents the persistance of theoscillating circuit. So far as I am aware I was the first lectancefunction wherein L represents This selectanceto point out this functionof a resonant receiving circuit which I have termed its selectance andpersistance, although I am aware that as early as April 24:, 1891, theratio of the potential difference at the terminals of the condenser tothe applied pressure in a circuit containing a condenser and aninductance coil reactance of the circuit to the resistance of thecircuit when p 2 C L I 1 (The Electrician, vol.

'26, p. 762), which expression, however, while algebraically equivalentto my selectance and persistance functions, gave no information as tothe relations that must subsist between the electromagnetic constants ofa resonant circuit in order to effect the maximum selectance andpersistance.

In Figs. 5 and 6 the condensers C'1 perform the functions set forth inmy Letters Patent No. 767 ,99 I, and therefore need not be furtherdescribed herein.

It is to be distinctly understood that the various transformers employedin the various systems described in this specification are illustratedmerely conventionally and that in actual practice they may be step-uptransformers or step-down transformers as occasion may require, and alsothat where, as in Figs. 1, 2 and 3, a plurality of circuits areconnected inductively in series by means of such transformers, thetransformers are all arranged to transform in the same direction and toimpress the energyof the source upon the elevated conductor or theelectric translating device, as the case may be, at increased potential,if increased potential be desired, or at increased current, if increasedcurrent be desired.

I make no claim in the present application to the method which may becarried into effect by the apparatus hereinafter claimed as such methodforms the subject matter of a divisional application Serial No. 267,L82,filed June 29, 1905.

I do not wish to be limited to the exact details of apparatus andcircuit arrangements herein described and conventionally illustrated.because many modifications may be made therein by those skilled in theart Without departing from the spirit of my invention; but

I claim, broadly, as my invention 1. In a system of selective electricsignaling, a transmitting system comprising means for radiating asubstantially continuous train of electromagnetic signal waves and meansfor varying the amplitude of said waves in accordance with the sonorousvibrations of articulate or other sounds, in combination with areceiving system comprising means for selectively absorbing the energyof said waves and means quantitatively responsive to the variations inthe amplitude thereof.

2. In a system of selective electric signaling,

sorbing the energy of said waves and means for reproducing said sounds.

3. In asystem of selective electric slgnahng, a transmitting systemcomprising means for developing a practically continuous train ofelectrical oscillations of substantially constant amplitude, means forvarying the amplitude of said electrical oscillations by and inaccordance with the sonorous vibrations of articulate or other sounds,and means for impressing said electrical oscillations so varied inamplitude upon an elevated transmitting conductor, whereby a practicallycontinuous train of electromagnetic waves varied in amplitude inaccordance with said sonorous vibrations is developed, in combinationwith a receiving system comprising means for selectively absorbing theenergy of said waves and means for reproducing said sounds.

4c. In a system of selective electric signaling, a transmitting systemcomprising vmeans for radiating a practically continuous trainofelectromagnetic waves of definite frequency and of substantially uniformamplitude, and avariable resistance transmitter'for varying theamplitude of said waves by and in accordance with the vibrations of theair accompanying vocal or other sounds, in combination with a receivingsystem comprising a resonant receiving circuit attuned to the frequencyof said electromagnetic waves and means included in said resonantcircuit for reproducing said sounds.

5. In a system of selective electric signaling, a transmitting systemcomprising means for radiating a practically continuous train ofelectromagnetic waves of definite frequency and of substantially uniformamplitude, and means for varying the amplitude of said waves by and inaccordance with the sonorous vibrations of articulate or other sounds,in combination with a receiving system comprising a resonant receivingcircuit attuned to the frequency of said electromagnetic waves and meansassociated with said resonant circuit for reproducing said sounds.

6. In a system of selective electric signaling, a transmittingsystemcomprising a sonorous circuit for developing a practically continuoustrain of electrical oscillations of substantially constant amplitude, avariable resistance transmitter associated with said sonorous circuitfor varying the amplitude of said electrical oscillations by and inaccordance with the sonorous vibrations of articulate or other sounds,and means for impressing said electrical oscillations so varied inamplitude upon an elevated transmitting conductor, whereby a practicallycontinuous train of electromagnetic waves varied in amplitude inaccordance with said sonorous vibrations is developed,

in combination with a receiving system comprising a resonant circuit forselectively absorbing the energy of said waves, and a bolometer finewire or strip included in said resonant circuit.

7. In a system for the transmission and reception of vocal or othersounds, including articulate speech, without the use of guiding wires, atransmitting system comprising a transmitting conductor, means fordeveloping a substantially continuous train of electromagnetic waves andmeans for modifying the amplitude of such waves in accordance with theair vibrations accompanying the sounds to be transmitted, in combinationwith a receiving system comprising a receiving conductor adapted toreceive the energy of such modified waves and means for converting theenergy of the electrical oscillations thereby produced in said conductorinto air Waves corresponding to said sounds.

8. In a system of electric signaling, a transmitting conductor, asonorous circuit, associated therewith andadapted to develop therein asubstantially continuous train of electrical oscillations ofsubstantially constant amplitude, and a circuit, containing a condenserand an inductance coil, associated with said sonorous circuit andcontaining means whereby its electromagnetic constants may be varied inaccordance with the air vibrations accompanying vocal or other sounds,in combination with an elevated receiving conductor adapted to absorbthe energy of said electromagnetic waves and means associated therewithfor converting the energy of the resulting electrical oscillations intosound waves.

In testimony whereof I have hereunto subscribed my name this 16th day ofJune, 1905.

JOHN STONE STONE.

Witnesses:

BRAINERD T. JUDKINs, GEORGIA A. HIGGINS.

